In addition, we detected the overexpression of a number of proteins involved in the oxidation–reduction process in the COVID-19 lung, which included glutamate-cysteine ligase, glutathione peroxidase 1, arginase, methylenetetrahydrofolate dehydrogenase 1, guanosine monophosphate reductase 2, thioredoxin, CP, peroxiredoxin 1, and acid phosphatase 1. Here, GMPR2 is linked to COVID-19.